Optimized Design of Levitation Current Regulator for Bearingless Motor

The complex and varied application conditions place high demands on the levitation current control performance of the bearingless motor because levitation current control quality directly influences the characteristics of the levitation force. This article focuses on optimizing the design of the levitation current control scheme based on the deadbeat control algorithm to enhance the high dynamic performance. In order to overcome the inherent drawbacks, including digital control delay, model parameter errors, and high-frequency noise that exist in deadbeat control, several novel and simple solutions are proposed. First, the effect of inherent problems on the levitation current control is given a quantitative analysis to serve as a theoretical basis. Then, a dual-sampling current prediction scheme based on a two-stage algorithm execution mechanism is proposed to compensate for the digital control delay and ensures the complete execution of the algorithm. Moreover, a real-time model parameter correction scheme based on the dual-sampling currents is proposed to solve the model parameter error. As for the high-frequency noise suppression, a scheme based on the deviation weight assignment is proposed by reasonably allocating the weight of the current vector deviation. Finally, the feasibility and superiority of the proposed levitation current regulator design scheme are verified by simulations and experiments on a bearingless motor pump.